http://dx.doi.org/10.1590/1809-4392201305162

A new species of Dichaea (Orchidaceae) for northern Brazil

Jefferson José VALSKO1, Amauri Herbert KRAHL2*, Ana Sofia Sousa de HOLANDA2, Charles Eugene ZARTMAN2

1 Universidade Federal do Amazonas, Programa de Pós-Graduação em Diversidade Biológica, Rua Gal. Rodrigo Otávio Jordão Ramos, 3000, Japiim I, Manaus, AM, Brasil. 2 Instituto Nacional de Pesquisas da Amazônia, Programa de Pós-Graduação em Botânica, Av. André Araújo, 2936, Aleixo, Manaus, AM, Brasil. * Corresponding author: [email protected]

ABSTRACT Dichaea is the largest genus of the subtribe Zygopetalinae and holds it’s the highest species diversity in South America. Therefore, this study aims to describe a new species of Dichaea, which occurs in northern Brazil, Dichaea bragae Valsko, Krahl & Holanda. The new species was collected in the north of Manaus in an area of ombrophilous forest and flowered when cultivated. The epithet honors Dr. Pedro Ivo Soares Braga (in memoriam), orchidologist who conducted several studies in the Brazilian Amazon. This new species show a affinity with Dichaea tenuis C. Schweinf., however it is differentiated both vegetatively and on labellum morphology. KEYWORDS: Taxonomy, Amazonas, epiphyte, dense ombrophilous forest.

Uma nova espécie de Dichaea (Orchidaceae) para o norte do Brasil

RESUMO Dichaea é o maior gênero da subtribo Zygopetalinae e possui sua maior diversidade de espécies na América do Sul. Diante disto, este trabalho teve o objetivo de descrever uma nova espécie de Dichaea ocorrente na região norte do Brasil, Dichaea bragae Valsko, Krahl & Holanda. A nova espécie foi coleta ao norte de Manaus em área de floresta ombrófila e floresceu em cultivo. O epíteto é em homenagem ao Dr. Pedro Ivo Soares Braga (in memorian), orquidólogo que realizou vários estudos na Amazônia brasileira. A nova espécie possui afinidade com espécies de Dichaea seção Dichaeopsis, contudo são diferenciadas vegetativamente e na morfologia do labelo. PALAVRAS CHAVE: Taxonomia, Amazonas, epífita, floresta ombrófila densa.

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The genus Dichaea was described by Lindley (1833) and leaf sheaths. These leaf sheaths are about 12.2 mm long holds the largest number of species belonging to the subtribe and 3.6 mm in width, are glabrous with entire margin and Zygopetalinae (Chase et al. 2003; Whitten et al. 2005) and light green coloring. Leaves are near 22 mm long and 5.6 comprises nearly 100 species (Pupulin 2007) distributed from mm in width, are elliptical-shaped with rounded base and Mexico to Bolivia and Argentina as well as the West Indies, apiculate apex. Leaf blades present articulate base with leaf presenting its highest diversity in South America (Dodson sheaths and are spaced among one on other, in addition to 2004). Ecuador presents 40 species recorded in the genus presenting themselves as deciduous, glabrous, entire margin (Dodson 2004), Costa Rica hosts 29 species (Pupulin 2007) and light green colored. The inflorescence is one-flowered, and Brazil 25 species, with 11 of them being endemic, as well solitary and with 6.8 mm long, in addition to emerging as 18 documented species in the Brazilian Amazon (Barros et from in between the leaf sheaths. The pedicel is about 3.83 al. 2013). Fourteen of the latter are to be found in the state mm long and shows to be glabrous with two tubular bracts of Amazonas (Barros et al. 2013). on its base. Both bracts have sharp apex, entire margin and Since the original description of the genus, other taxonomic are slightly greenish white- colored. The outer bract measures treatments including: e.g. Cogniaux (1904-1906); Folsom about 2.9 mm long and 1.1 mm in width and the inner one (1987); Folsom (1996). Presently, four sections are recognized 2.8 mm long and 1.1 mm in width. The ovary and pedicel for the genus Dichaea (Cogniaux 1904-1906): Dichaea section together measure about 1 mm long and 0.3 mm in width Dichaea, which presents pilous ovary and non-articulate and are glabrous. Flowers are green-colored on the sepals and leaves; Dichaea section Dichaeastrum, with glabrous ovary petals and the labellum is white. Flowers didn’t put forth no and non-articulate leaves; Dichaea section Dichaeopsis, which aroma at all. The dorsal sepal measures about 3.6 mm long involves plants presenting glabrous ovary and articulate leaves; and 1.2 mm in width and is lanceolate-shaped, acute-apexed and finally,Dichaea section Pseudodichaea, characterized and round-based, in addition to being symmetrical and with by the pilous ovary and articulate leaves. Pabst and Dungs entire margin. Lateral sepals have about 4.9 mm long and (1977) divided the genus into five groups taking the leaves 1.9 mm in width and likewise shaped. Petals measure near (articulation and deciduousness), ovary (glabrous or pilous) 4.1 mm long and 1.7 mm in width, lanceolate-shaped, acute and labellum characteristics into account. Even though this apex and round-based as well, in addition to being slightly genus treatments are limited to Brazilian species, its sections asymmetrical and with entire margin. The labellum measures comprise all aforementioned authors combinations for the about 4.3 mm long and 3.7 mm in width and shows to be genus, as a whole. The present study aims to describe a new 3-lobed. Its base is unguiculate, oblong and measures nearly species of Dichaea: Dichaea bragae Valsko, Krahl & Holanda. 2.3 mm long and 0.4 mm in width, in addition to being The terminology used to describe the characteristics is based glabrous and with entire margin. The labellum blade have on Radford et al. (1974) and Dressler (1993). about 2.5 mm long and 3.7 mm in width, is triangular and apiculate-apexed. The labellum lateral lobes are linear and Dichaea bragae Valsko, Krahl & Holanda, sp. nov. Type: sharp-curved, round-apexed and with entire margin. The BRASIL: Amazonas: Manaus, BR 174, KM 72, Projeto gynostemium is near 1 mm long and 0.6 mm in width, is Dinâmica Biológica de Fragmentos Florestais (PDBFF), erect and glabrous. The anther cap measures approximately 0 0 Fazenda Dimona, S 2 21’ and W 59 57’, 7/V/2012, fl., 1.6 mm long and 1.4 mm in width, being round, symmetrical, flowered in cultivation in 7.IV.2013, J.J. Valsko 108 (Holotype glabrous, with entire margin and green-colored. The species INPA). (Figure 1A-E, Figure 2A-D). presents four pollinia being two different pairs. The pollinia Dichaea bragae is similar to D. tenuis yet they differentiate measures about 0.1 mm in diameter and are yellowish-colored by the fact that D. bragae holds elliptical leaves with apiculate and circular-shaped. The stipe is triangular in dorsal view and apex being wider than those of D. tenuis that presents aciculate the viscidium is elliptical. The fruit is about 7.5 mm long and and semiterete leaves. Furthermore, D. bragae presents 2.5 mm in width, glabrous, ovate and light green-colored. elliptical sepals and petals and the labellum lateral lobes show Etymology, phenology, distribution and habitat: the to be sharply curved, being that D. tenuis presents ovate sepals epithet honors Dr. Pedro Ivo Soares Braga (in memoriam), and petals and round labellum lobes. The labellum lateral lobes orchidologist who developed several studies with Orchidaceae curvature is similar to that of D. cornuta, however, the latter in the Brazilian Amazon (Storti 2011). It flowered in presents larger floral parts. cultivation between March and May. The flowers last The plant is epiphytic and cespitose. Its roots are between approximately three days. Dichaea bragae occurs in dense 1.5 and 1.8 mm in diameter and whitish, slightly fleshed and ombrophilous forest at an altitude of 90-100 meters in the emerge from the stem base. The stem is from 4.3 to 20.6 cm Dimona farm belonging to the Biological Dynamics of Forest long and nearly 3.3 mm in diameter and shows to be lengthy Fragments Project (PDBFF). The type specimen was found in and not branched, cylindrical-shaped and to be covered by an area where flooding occurs for a short period, resulting in

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Figure 1. Dichaea bragae Valsko, Krahl & Holanda. A. General aspect of the plant. B. Flower. C. Floral parts. D. Gynostemium. E. Pollinia. the formation of small ponds within the forest. It is observed which always hold articulated and deciduous leaves, glabrous attached to the phorophytes, about four to eight meters from ovary and a narrow and long labellum base. This species is the ground in low light environment. related to Dichaea tenuis C. Schweinf., however it differs both Comments: Dichaea bragae presents morphological in the vegetative aspect and floral morphology (labellum). characteristics that fit within theDichaea section Dichaeopsis Dichaea bragae presents apiculate-apexed, elliptical leaves, (Cogniaux 1904-1906). The species fits in theD. panamensis larger (ca. 5.64 mm) than those of D. tenuis which present group, According to Pabst and Dungs (1977), the plants of 9-11 mm wide and acuminate-apexed semiterete acicular

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Figure 2. Dichaea bragae Valsko, Krahl & Holanda. A. General aspect of holotype. B. Image of the plant. C. Flower. D. Labellum.

leaves, h. The floral parts (sepals and petals) ofD. bragae are sharp curve in D. bragae lateral lobes clearly differs from that lanceolate while in D. tenuis they are ovate, in addition, the present in D. trulla and D. glauca. D. bragae labellum holds linear, sharp-curved, side lobes while the D. tenuis labellum is widely rounded (Schweinfurth 1961). ACKNOWLEDGMENTS In general, the curvature of the side lobes in D. bragae is the The authors acknowledge the Biological Dynamics main characteristic distinguishing this species from all other of Forest Fragments Project (PDBFF) for all the logistics she in the same genus. However, in addition to D. bragae, the provided; and graduate program in botany from the National species Dichaea cornuta S. Moore also presents sharp-curved Institute of Amazonian Research (INPA) for the support lateral lobes, yet D. bragae holds smaller floral parts (sepals, provided. petals and lip) (e.g. dorsal sepals = 3.6 mm, labellum = 4.3 mm) than those of D. cornuta by having larger floral parts (e.g. REFERENCES dorsal sepals = 8.5 mm, labellum = 6 mm). In the phylogenetic Barros, F.; Vinhos, F.; Rodrigues, V.T.; Barberena, F.F.V.A.; Fraga, of Neubig et al. (2009) the Dichaea section Dichaeopsis is C.N.; Pessoa, E.M.; Foster, W.; et al. (Orgs.). Lista das espécies da shown to form some clades bearing closely related species. flora do Brasil. Jardim Botânico do Rio de Janeiro, Rio de Janeiro. Dichaea trulla Rchb. f. that resembles vegetatively with D. (http://floradobrasil.jbrj.gov.br). Accessed on 29/09/2013. bragae being one Among them, and Dichaea glauca (Sw.) Chase, M.W.; Freudenstein, J.V.; Cameron, K.M.; Barrett, Lindl is mentioned to be among them as well. However the R.L. 2003. DNA data and Orchidaceae systematics: a new

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